@mixin flex($grow:1,$basis:0){
    flex-grow: $grow;
    flex-basis: $basis;
    max-width: 100%;
}

/* 自动栅格系统 */
@mixin fluid-col ($length){
    @for $index from 1 through $length {
        .row {
            & > .col-#{$index} {
                padding-left:$span-padding;
                padding-right:$span-padding;
            }
        }
        .col-#{$index} {
            float: left;
            width: percentage(1 / $span-length * $index);
        }
    }
}